1. Field of the Invention:
This invention relates generally to printing presses, and specifically to a printing press idle roller braking system for use with web fed printing presses.
2. Description of the Prior Art:
Idle rollers are commonly used in large and small printing presses to route web sheet paper through the press during the printing process; they do not serve to print images on the web sheet, but rather serve merely to direct web sheets through the printing press frame. In a large press, as many as two hundred idle rollers are employed to route the web sheets. Such idle rollers are generally four inches in diameter and constructed of steel or high impact plastic. Each of the idle rollers rotate freely about a shaft which is secured to the printing press frame. They are not coupled to any means for rotation; rather, they "free wheel" about a shaft at high speeds due to the frictional circumferential contact between the outer circumferential periphery of the outer roller and the web sheet which is pulled through the printing press at very high speeds. It is not uncommon for idle rollers to rotate at speeds in excess of fifteen hundred revolutions per minute. As stated above, the spinning of the cylindrical idle roller is caused entirely by contact with the web sheet as it is pulled through the printing press.
Periodic maintenance must be performed upon the cylindrical idle rollers to ensure the proper operation of the printing press. More specifically, ink and lint from the web sheet tends to accumulate on the outer circumferential periphery of the cylindrical idle roller during the printing process. Such accumulation of ink and lint often interferes with the printing process by producing wrinkles in the web sheet. Therefore, in the prior art, printing presses must be periodically shut down to allow for cleaning of the cylindrical idle rollers with a solvent. To avoid shutting down the printing presses, some printers actually placed solvent on the roller trains, and sheets of paper in the printing press to allow for "self-cleaning" of the idle rollers while the printing press is operated. This practice, however, proved to be hazardous, resulting in many health problems for printers, including skin irritations. Use of the solvents may cause respiratory problems, depression, and other harmful effects on personnel. However, solvents currently used in the industry have come under recent scrutiny from the Occupational Safety and Health Administration (OSHA). In fact, current OSHA guidelines limit the use of certain previously widely used solvents.